Connectors with large numbers of contacts that can be mated and unmated from contacts of corresponding connectors, are useful in a variety of applications, such as to make a large number of connections in large computers. For example, in one application numerous twisted wire pairs lead to the rear of connector frames and connect to pairs of socket contacts in the connector. Very high densities of contacts are required, such as about 400 contacts per square inch in one application. The closely spaced pairs of contacts must provide a known uniform degree of cross talk between contacts with high reliability, and the contact pairs must be easily replaceable in the event that a contact malfunctions. A contact assembly which could meet these requirements would be of considerable value.